New 2012 iMac as external display for PC

macrumors member

I am interested in purchasing the new 27" iMac in December and I've recently purchased a new PC which will be used solely for gaming. My desk space is limited so I 'd like to use the iMac as a display for my PC.

The PC motherboard has thunderbolt connectivity and states it can output to thunderbolt displays. The mother board is a Gigabyte Z77x UP4 TH

There are numerous videoson youtube (and blog posts on the net) which show thunderbolt PC's connected to the Apple Thunderbolt Display, and it works fine. My question is, instead of a Thunderbolt Display, can I use a 27" 2012 iMac in Target Display Mode? Does target display mode simply turn the iMac into a monitor, and should it technically work with a thunderbolt enabled PC?

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Quick thread summary for new readers.
- A user has confirmed it's possible to use the thunderbolt iMac as a display for a laptop (HP Spectre XT > 21.5" 2012 iMac).
- Others can't reproduce, and the iMac is being recognized as a "PCI to PCI Bridge" under the Windows 7 Devices list.
- Setting initial display to igfx, increasing reserved IO for thunderbolt and enabling internal graphics in the PC BIOS does not seem to help.
- The latest bootcamp drivers (released with 10.8.3) don't seem to help either.
- The iMac cannot be used as a screen for an xbox or PS3 since it only accepts thunderbolt video input.

thread startermacrumors member

I think I may have finally found an answer. Plugging the thunderbolt into the PC motherboard will only use the integrated graphics unless you configure it to use otherwise using Virtu MVP. This review and this video explain it.

So the only question I have now is: Does Target Display Mode simply turn the iMac into a display (so it behaves exactly the same as a Thunderbolt display)? It will be connected to the PC using a thunderbolt cable.

thread startermacrumors member

The PC would be used for high end gaming - Battlefield 3 (and future games) on max settings with good framerate, etc. The iMac could run the game, just not as smoothly .. and the PC can always be upgraded in a few years if needed.

If I just needed Windows for certain programs, I would definitely use Bootcamp.

The link in my other post says the Thunderbolt Display works with the PC motherboard:

Code:

The great news is that this is compatible with Apple's new Thunderbolt display - we now have a way to connect these screens directly to a PC.

Does Target Display Mode on the 2012 iMac essentially turn the iMac into an external display (so it basically becomes a Thunderbolt Display)?

macrumors 68030

2. If it can be used as a display, what do I need to purchase when ordering my PC? Is it the motherboard which needs to have thunderbolt capability, such as this? Does the PC graphics card matter?

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I can't recall the company (was it Asus?), but someone has a Thunderbolt card that slots into a handful of their specific motherboards and connects outside the case to a GPU with DisplayPort. So you can get your PC's GPU as Thunderbolt input to the iMac in Target Display that way. I haven't read of anyone that's tried it yet though.

macrumors newbie

Thanks guys. I'm pretty confident the links in post #3 are the right steps to take.

I just need to know if Target Display Mode on iMac's simply turns the mac into a display? (so it functions exactly the same as the Thunderbolt Display)

Either way, I'll likely be purchasing the mac when it's available so I'll report back if it works.

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It won't work. Don't do it. The iMac won't enter Target Display Mode from a Windows source, even if you have a Thunderbolt motherboard and Thunderbolt cable. I tried, and in fact I purchased a new motherboard and transplanted all my parts from my gaming machine to try to do this. No luck.

thread startermacrumors member

It won't work. Don't do it. The iMac won't enter Target Display Mode from a Windows source, even if you have a Thunderbolt motherboard and Thunderbolt cable. I tried, and in fact I purchased a new motherboard and transplanted all my parts from my gaming machine to try to do this. No luck.

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Thanks for the suggestion. I bought the new PC regardless, but I might hold off on the new iMac if it doesn't work.

I asked in my Apple store the other day and they said technically it should work (since it works with the thunderbolt display), but they haven't seen any other customers do it before so they weren't 100% sure. They said all products which are purchased over the Christmas period can be returned (even after use) until January 7 and said I could try it. Then if it didn't work, I could simply return the iMac and TB cable for a full refund.

macrumors 6502a

It won't work. Don't do it. The iMac won't enter Target Display Mode from a Windows source, even if you have a Thunderbolt motherboard and Thunderbolt cable. I tried, and in fact I purchased a new motherboard and transplanted all my parts from my gaming machine to try to do this. No luck.

Click to expand...

That sucks. What kind of motherboard was this, maybe it's an issue with this particular motherboard? I talked to Apple support, and they said it should work. It works when you're doing the same thing with an Apple Thundebolt Display (I've seen it on youtube), so it doesn't make sense that it won't work on an iMac.

thread startermacrumors member

I will likely be purchasing the 27" iMac when it's released, so I'll give it a try. It may require some minor changes to the PC settings (such as using integrated graphics + discrete with Virtu MVP).

The only two concerns I have is:
a. the iMac's Target Display Mode may not accept Windows PC input (it may have been limited by its software to only accept other macs)
b. in Windows, all thunderbolt devices need to be plugged in when the PC is turned on. Even though the iMac would be plugged in, it wouldn't be in Target Display Mode, so the PC may not recognise it as a display when it boots up (which means it never will since PC thunderbolt devices cannot be hot swapped yet).

thread startermacrumors member

It won't work. Don't do it. The iMac won't enter Target Display Mode from a Windows source, even if you have a Thunderbolt motherboard and Thunderbolt cable. I tried, and in fact I purchased a new motherboard and transplanted all my parts from my gaming machine to try to do this. No luck.

Click to expand...

Did you change any settings in your BIOS so integrated graphics were set to default on the PC, etc? Some thunderbolt motherboards also restrict video output to the first thunderbolt port if there is a DVI-D monitor connected as a secondary display. From the manual: "When a monitor is connected to the DVI-D port, the MDP2 Thunderbolt port can support Thunderbolt storage device(s) only."

Did you also update the intel graphics drivers to the latest version before trying?

macrumors member

I am interested in purchasing the new 27" iMac in December and I've recently purchased a new PC which will be used solely for gaming. My desk space is limited so I 'd like to use the iMac as a display for my PC.

The PC motherboard has thunderbolt connectivity and states it can output to thunderbolt displays. The mother board is a Gigabyte Z77x UP4 TH

There are numerous videoson youtube (and blog posts on the net) which show thunderbolt PC's connected to the Apple Thunderbolt Display, and it works fine. My question is, instead of a Thunderbolt Display, can I use a 27" 2012 iMac in Target Display Mode? Does target display mode simply turn the iMac into a monitor, and should it technically work with a thunderbolt enabled PC?

Click to expand...

Hate to get off topic but it didn't seem I could PM you. What setup did you assemble for your gaming system? How much did it run you? I couldn't get myself to get PC but I can't help but be curious.

macrumors regular

I will likely be purchasing the 27" iMac when it's released, so I'll give it a try. It may require some minor changes to the PC settings (such as using integrated graphics + discrete with Virtu MVP).

The only two concerns I have is:
a. the iMac's Target Display Mode may not accept Windows PC input (it may have been limited by its software to only accept other macs)
b. in Windows, all thunderbolt devices need to be plugged in when the PC is turned on. Even though the iMac would be plugged in, it wouldn't be in Target Display Mode, so the PC may not recognise it as a display when it boots up (which means it never will since PC thunderbolt devices cannot be hot swapped yet).

Click to expand...

Not sure if this is helpful to you or not since it's an imprecise comparison. but.....

I had success connecting a new HP Spectre laptop with a thunderbolt port to a 2012 21.5" iMac in target display mode.

I used Apple's thunderbolt cable. The PC needed to download some drivers, but did it automatically. After that, the display works either as primary or as a second display.

What did not work was a keyboard and mouse connected to the mac though I had no expectation it would

PS: the hp in question was using intel integrated graphics (4000). It does not have a dedicated graphics card

macrumors 6502a

Not sure if this is helpful to you or not since it's an imprecise comparison. but.....

I had success connecting a new HP Spectre laptop with a thunderbolt port to a 2012 21.5" iMac in target display mode.

I used Apple's thunderbolt cable. The PC needed to download some drivers, but did it automatically. After that, the display works either as primary or as a second display.

What did not work was a keyboard and mouse connected to the mac though I had no expectation it would

PS: the hp in question was using intel integrated graphics (4000). It does not have a dedicated graphics card

Click to expand...

Just to confirm (because this is great, unexpected news!): You connected a laptop running Windows to your 2012 iMac via thunderbolt, and you could use your 2012 iMac as an external monitor for the Windows laptop? I've several accounts of this not being possible with the 2011 iMac (haven't tried it myself though)..

macrumors regular

Just to confirm (because this is great, unexpected news!): You connected a laptop running Windows to your 2012 iMac via thunderbolt, and you could use your 2012 iMac as an external monitor for the Windows laptop? I've several accounts of this not being possible with the 2011 iMac (haven't tried it myself though)..

Click to expand...

I didn't test it extensively since although it was my iMac it wasn't my laptop, but yes it worked.

One very minor wrinkle was that it was not "hot" pluggable. In other words I could not just plug the two together after the were both powered on. The laptop needed to be started up connected to the iMac for it to recognize it as a display.

The other key thing (and I'm guessing a bit) is that the windows machine definitely loaded at least one driver the first time it was plugged in though I'll be darned if I can figure out what driver was loaded. The OS is Windows 8 as well though I'm not sure that matters

macrumors 6502a

I didn't test it extensively since although it was my iMac it wasn't my laptop, but yes it worked.

One very minor wrinkle was that it was not "hot" pluggable. In other words I could not just plug the two together after the were both powered on. The laptop needed to be started up connected to the iMac for it to recognize it as a display.

The other key thing (and I'm guessing a bit) is that the windows machine definitely loaded at least one driver the first time it was plugged in though I'll be darned if I can figure out what driver was loaded. The OS is Windows 8 as well though I'm not sure that matters

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Nice! Maybe Windows 8 is the reason it worked for you, or maybe the new 2012 iMac has an improved thunderbolt connection/firmware. Anyway, it's possible, that's the main thing. The lack of working "hot" connection is well known, and Microsoft is supposedly working on a fix. Thanks for the good news!

thread startermacrumors member

Not sure if this is helpful to you or not since it's an imprecise comparison. but.....

I had success connecting a new HP Spectre laptop with a thunderbolt port to a 2012 21.5" iMac in target display mode.

I used Apple's thunderbolt cable. The PC needed to download some drivers, but did it automatically. After that, the display works either as primary or as a second display.

What did not work was a keyboard and mouse connected to the mac though I had no expectation it would

PS: the hp in question was using intel integrated graphics (4000). It does not have a dedicated graphics card

Click to expand...

Thanks for the reply - very good news! I think you're the only person who has reported this as working so far. If anyone else has done it with a thunderbolt iMac, they certainly haven't posted about it.

The thunderbolt port on my PC will also use intel integrated graphics 4000 (but will also have access to the dedicated graphics using Virtu MVP software).

So the drivers downloaded automatically? You're not sure what ones they were exactly? My PC is Windows 7 (not 8) so hopefully it works the same as yours.

macrumors regular

Thanks for the reply - very good news! I think you're the only person who has reported this as working so far. If anyone else has done it with a thunderbolt iMac, they certainly haven't posted about it.

The thunderbolt port on my PC will also use intel integrated graphics 4000 (but will also have access to the dedicated graphics using Virtu MVP software).

So the drivers downloaded automatically? You're not sure what ones they were exactly? My PC is Windows 7 (not 8) so hopefully it works the same as yours.

Does sound play through the iMac aswell, or is it just the video?

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I wish I could give you more info than I have. It was one of those things where my friend was showing me his new laptop, we noticed the thunderbolt port, and it was a " I wonder if this would work" kind of thing.

I can't say if the sound did or did not play through the iMac. I kind of think no, at least the startup sound seemed to come from the laptop.

The very first time we connected the hp to the iMac, windows came up with the "getting drivers" message similar to what you get with most new USB devices when you plug them in to a PC the first time.

thread startermacrumors member

Ah sorry, didn't realise it was your friends laptop. Thanks again for the replies. Even with the small amount of info, you've definitely helped a lot since I now know it's possible (at least on Windows 8).

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